Skin Cells Show Potential to Grow Into Organs

The Yomiuri Shimbun, August 11, 2006

Resembling an embryonic stem cell, a new pluripotent cell has been generated using a mouse skin cell by researchers at Kyoto University in Tokyo, Japan.

A U.S. scientific journal named Cell recently noted in their online issue that Prof. Shinya and Assistant Prof. Kazutoshi created a new pluripotent cell that has comparable characteristics as embryonic stem cells. This will give the new cell the capability to grow into organs and tissues just like embryonic cells. The professors named the new cell induced Pluripotent Stem, or iPS for short.

Extracted from an embryo, the use of the embryonic stem cell in medicine is ethically controversial. Since an embryo is not involved, the iPS cells would purge any ethical concerns. Although the new cells are derived from mouse skin cells, the future may bring the emergence of human iPS cells.

Adult-stem cell therapy has shown its effectiveness, but the thought of converting adult stem cells and making them function similar to embryonic stem cells would open even larger doors for treating patients. Individuals undergoing transplants could have new organs with identical genes as their own. There would be no immune response clearing the issue of post operative rejection, and also, no ethical dilemma.

The group speculated that amid the important gene factors in an embryonic stem cell, there should be a number that can reprogram somatic cells and induce pluripotency that are characteristic to the factors in an embryonic stem cell in early development.

Taking a skin cell extracted from a mouse tail, the researchers picked up 24 candidate gene factors and implanted four of those gene factors, including Sox2, into the selected skin cell and cultivated it.

Taking on a comparable pattern to embryonic stem cells after only two weeks, the skin cell with the four gene factors changed.

In three weeks, the new iPS cells formed tumors called teratomas containing nerves, digestive tissues and cartilage after it was reintroduced to the mouse body. The cell also developed heart muscle cells and nerves, and displayed signs of a pulse on a culture dish. This would validate the cells pluripotency.

iPS cells can be created without involving a generative cell using this method.

Yamanaka said, "We'll continue the research and try to make iPS cells from human skin cells, and then be able to offer regenerative medical treatment using the cell."

"It's been considered impossible to create an ES cell from a somatic cell without using cloning technology, but (Shinya's group) succeeded in generating a cell similar to an ES cell from a mouse somatic cell. This brought hopes that the same technique could be applied to human cells," stated Teruhiko a team leader of Riken Center for Developmental Biology.

He added, "Regenerative medicine will definitely make progress in this direction in the future."